Mix together yogurt half a teaspoon of the garam masala leave in a bowl to marinate for 1- 2 hrs.

Heat oil in large pan over medium heat add whole spices...fry for a few seconds before adding onions, garlic and ginger ....cook until onions until soft.

Add lamb marinated mixture to saucepan and cook for 20 minutes on a medium to low heat.

Add the rest of the ground spices and season .....cook through as a paste for a few minutes then add the tinned tomatoes cook for a few minutes on a medium heat then add 3/4 pint of water *(I always add a teaspoon arrowroot to water to help with thickening)
Bring to boil and then turn down on a low heat and simmer ....cook gently for 1 1/2 hours on a very low heat.... stirring occasionally .... topping up with water when necessary
Garnish with the Coriander.